A model of Greenland ice sheet deglaciation constrained by observations of relative sea level and ice extent

Abstract

. (2014) 'A model of Greenland ice sheet deglaciation constrained by observations of relative sea level and ice extent.', Quaternary science reviews., 102 . pp. 54-84. Further information on publisher's website:http://dx.doi.org/10.1016/j.quascirev.2014.07.018Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Quaternary Science Reviews. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reected in this document. Changes may have been made to this work since it was submitted for publication. A denitive version was subsequently published in Quaternary Science Reviews, 102, 2014Reviews, 102, , 10.1016Reviews, 102, /j.quascirev.2014 Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACT An ice sheet model was constrained to reconstruct the evolution of the Greenland Ice Sheet (GrIS) from the Last Glacial Maximum (LGM) to present to improve our understanding of its response to climate change. The study involved applying a glaciological model in series with a glacial isostatic adjustment and relative sea-level (RSL) model. The model reconstruction builds upon the work of Simpson et al. (2009) through four main extensions: (1) a larger constraint database consisting of RSL and ice extent data; model improvements to the (2) climate and (3) sea-level forcing components; (4) accounting for uncertainties in non-Greenland ice. The research was conducted primarily to address datamodel misfits and to quantify inherent model uncertainties with the Earth structure and non-Greenland ice. Our new model (termed Huy3) fits the majority of observations and is characterised by a number of defining features. During the LGM, the ice sheet had an excess of 4.7 m ice-equivalent sea-level (IESL), which reached a maximum volume of 5.1 m IESL at 16.5 cal. ka BP. Modelled retreat of ice from the continental shelf progressed at different rates and timings in different sectors. Southwest and Southeast Greenland began to retreat from the continental shelf by ~16 to 14 cal. ka BP, thus responding in part to the Bølling-Allerød warm event (c. 14.5 cal. ka BP); subsequently ice at the southern tip of Greenland readvanced during the Younger Dryas cold event. In northern Greenland the ice retreated rapidly from the continental shelf upon the climatic recovery out of the Younger Dryas to present-day conditions. Upon entering the Holocene (11.7 cal. ka BP)...

Simulation of the Greenland Ice Sheet over two glacial–interglacial cycles: investigating a sub-ice- shelf melt parameterization and relative sea level forcing in an ice-sheet–ice-shelf model

“…On the timescales of this study, the main processes driving this spatial and temporal variability is GIA (Rovere et al, 2016). The variability results from the interplay between the GrIS-driven local changes, as is typical for near-field regions and the non-local changes driven by the LIS and the IIS (Lecavalier et al, 2014). This is because Greenland sits on the resulting forebulge of the LIS.…”

“…This is mostly due to the reduction in the estimated contribution from the Antarctic Ice Sheet (AIS), derived from both modelling and observational studies. In addition, glacial isostatic adjustment (GIA) modelling studies have estimated the contribution of the GrIS to the LGM GMSL budget to be ∼ 5 m (Lecavalier et al, 2014), whereas most ice-sheet modelling-based studies indicate significantly less (typically < 2.5 m; average < 1 m) (Fyke et al, 2011;Letreguilly et al, 1991;Ritz et al, 1996). These lower estimates are possibly caused by restricting the glacial maximum extent to the PD coastline.…”

“…This approach has been adopted in many ice-sheet modelling studies, solving only for grounded ice and reconstructed an extended GrIS during glacial periods (i.e. Huybrechts, 2002;Lecavalier et al, 2014;Simpson et al, 2009). However, rather than the ice sheet evolving freely, it is preconditioned to match with the observational data and does not use any physically based principles.…”

Differences between the last two glacial maxima and implications for ice-sheet, δ18O, and sea-level reconstructions

“…(LGM at~24 ka) n/r n/r n/r n/r n/r n/r 5.6 to 14.3 n/r n/r n/r Argus et al, 2014. (ICE-6G) n/r n/r n/r n/r n/r n/r 13.6 n/r n/r n/r Huybrechts, 2002 (LGM at~21 ka) n/r n/r n/r n/r 2 to 3 n/r 14 to 18 n/r n/r n/r Huy2 (Simpson et al, 2009) n/r n/r n/r n/r 4.1 n/r n/r n/r n/r n/r Huy3 (Lecavalier et al, 2014) n/r n/r n/r n/r >4.7 n/r n/r n/r n/r n/r layer without planktonic foraminifera (e.g., Fenton et al, 2000 and references therein); only a few sea-level values could be recovered from this "aplanktonic" layer (Fig. 2b).…”

On the reconstruction of palaeo-ice sheets: Recent advances and future challenges

“…This has progressed from hand-tuned models (e.g. Tarasov and Peltier, 2002) to approaches that explore and quantify (to varying extents) uncertainties due 44 to climate forcing and glaciological model components Briggs et al, 2014) as well as uncertainties in the regional Earth rheology (Whitehouse et al, 2012;Lecavalier et al, 2014). The much expanded constraint of glaciological-self-consistency, however, can come with an expected cost.…”